also check recv buf?

[todo]

bagua-core/bagua-core-internal/src/communicators/mod.rs

Lines 391 to 396 in 2166d61

	// TODO: also check recv buf?
	assert_eq!(
	send_tensor.num_elements_allocated() % self.nranks,
	0,
	"tensors must be aligned before using allscatter"
	);

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This issue was generated by todo based on a TODO comment in 2166d61 when #19 was merged. cc @BaguaSys.